SUMMARY: Even though they&#39;re well past their warranties, the Mars Exploration Rovers, Spirit and Opportunity are acting remarkably spry. Opportunity has just wrapped up three days of hard driving, covering more distance than Spirit made in its first 70 days on Mars. It set a one-day record, reaching 177.5 metres (582 feet) on a single day. The rovers have been using their autonomous driving mode to set their own routes around obstacles without micromanagement from controllers on Earth.